Prosecutor Delia Matthews said: "The allegation is an abuse of trust in that he was the doctor of these children - boys as young as 11 who were cancer sufferers in his care."

The alleged offences date back to 2011 and relate to boys aged between 11 and 15.

He also faces two charges of making indecent images of a child and one count of voyeurism, in which it is alleged he secretly filmed somebody engaging in a sex act.

Wearing a dark blue suit, white shirt and tie, Bradbury, of Herringswell, Suffolk, spoke only to confirm his name, date of birth and address.

He did not indicate any likely plea and was bailed to appear before Cambridge Crown Court on July 11.

He left the court building via a rear entrance to avoid camera crews waiting outside.

Cambridge University Hospitals NHS Trust, which runs Addenbrooke's Hospital, has set up a helpline to be used "if parents, patients or former patients have any concerns".

The trust added it was working closely with the NSPCC.

The helpline, on 0800 389 8625, can be reached between 8am and 9pm on weekdays and 9am to 5pm at weekends.

Since the alleged offences, Bradbury has left his job at the hospital and has not worked there this year.

A trust spokesman said: "The news that Dr Myles Bradbury, formerly of CUH (Cambridge University Hospitals NHS Trust), has been charged with offences against children will be distressing for many patients, their families and staff.

"Our main priority at CUH is the safety of our patients.

"As soon as concerns were raised nine months ago, Dr Myles Bradbury was excluded from working at the trust and is no longer employed here.

"Since then we have worked closely with Cambridgeshire Police and partners, including the NSPCC, to make sure that individuals are contacted and support is offered throughout this difficult time."